Damping device for shutters



July l1, 1933.

A. G. sUTcLir-FE DAMPING DEVICE FOR sHUTTERs Filedsept.

WWW/M/lojlggl Patented July 11', 1933 DAMPJQNG DEVICE FOR SHUTTERS @shutters on the outer'side of the opening to close the latter against the ingress of rain, snow` or wind, Vwhen the fan is idle; .the shutter or shutters closing by gravity and being opened by the blast of the fan. EX-k 10., amples of this are shown in Letters Patent to R. A.. Ilg No: 1,189,572, July 4, 1916 and No. 1,482,398, February 5, 1924.

Practical experience with shutters of this type'has shown that they frequently become, 15 noisy under the action of the wind thereon,

andthe main object of the present invention is to lprovide an attachment 1n the general nature of andash-pot for so controlling the shutter. movement as to *prevent the shutterV 29;.yane or vanesfrom slamming vwhen opened or'closed by a blast of air from any other source than the fan itself, and,`at the same time, to allow the vanes to open freely under the action of the air pressure from the fan.

29;. In the accompanying drawing l have illus# trated one simple and practical embodiment of the invention, and referring thereto- Fig. 1 is a vertical section through a ventilating opening in an external wall of a build- 3Qgging, showing a Ventilating fan, a shutter frame, and a group of shutter vanes mounted therein and having my present invention applied thereto.

Fig. 2 is a fragmentary inner or rear eleva-- 3ligation of a corner portion of the' shutter frame and shutter, also showing my improved shutter control applied thereto.

Fig. 3 is a perspective detail of `a'portion of a single shutter vane and its spindle and Qi-vane controlling arm and link.

Fig. 4 is a detail View, in vertical section, of a modified form of dash-pot.

Fig. 5 is a perspective elevation of the dash-pot plunger shown in Fig. 4.

g Referring to the drawing, and first briefly describing the known parts substantially as disclosed in Letters Patent 1,189,572, hereinabove referred to, mayl designate an external wall of a building in which is 5Q-,oformed a VentilatingV opening 11. Within It has heretofore been known, in connec-- V Application filed ASeptember 16, 1929. Sera1No.'393,102. Y

said opening is mounted a' Ventilating :fan

12 that, in practice, is'usually driven by an electric motor (not shown).

Secured to the outer side lof the wall 10 and surrounding the Ventilating openlng 11 is a rectangular shutter frame 13, in and be,- y

PATENT OIFFlc-;"Yvl Y ARTHUR G. SUTGLIIIE, 0I" CHICAGO, ILLINOIS, AssIGNon TIo' ILG ELECTRIC VENTILAI- i ING COMPANY, or cIIIonc-o, ILLINOIS, e CORPORATION or LOUISIANA tween the vertical' sides of which are jo'u'rnaled a seriesof horizontal shutter spindles 14, herein shown as disposed in a Vertical plane.

each `of which comprises a rectangular' strip of sheet metal that ,is curled at its 'upper longitudinal edge around the spindle 14 as shown at 16. Thelower free longitudinal edge of each Vane 15 lis bent inwardly slightly, as

shown at 15, and said inwardly bent edge. overlaps the rounded upper edge of the neXt lowermost'vane', as clearlyshown in Fig. 1.

To secure simultaneous andequal opening and closingmovements ofthe several Vanes,

the latter are connected together by a mecha'-` Y nism which comprises a series of metal strips that are mounted on'the respective spindles 14, each of said strips comprising a downwardly and forwardly projecting arm 17 having an inturned forked end 18 that embraces one end edge of the vane 15, and a rearwardly extending arm 19. The outer ends of the arms 19 are pivotally united, as by screws or bolts 20, or any other suitable pivot joints, to a connecting link 21.

Describing now my improved shutter damping attachment, secured to the top of the shutter frame 13 is an angle bracket 22, to the depending limb of which is pivoted at 23 the upper closed end of a depending dash-pot cylinder 24, the lower end of which cylinder is open. Loosely slidable within the cylinder 24 is a dash-pot plunger 25, in which is Vsecured a plunger rod 26, that extends through the lower open end of the cylinder 24 and is curved outwardly and pivotally connected at 27 to the link 21.

In the dash-pot structure illustrated in Figs. 1 and 2, the plunger 25 is provided with a longitudinal duct 28, and overlying the top of the plunger and normally closing the upper end of the duct 28 is a valve member which sal p 60. 15' designates the shutter Vanes or blades,

The plunger 25 has a loose sliding fit in the cylinder 24, so that, as the plunger rises under the gravity-closing movement of the shutter vanes the air trapped above the plunger will slowly Work down between the side wall of the latter and the internal wall of the cylinder, thus retarding the gravity closing movements of the shutter vanes 15. On the other hand, when the fan starts up the vanes will open freely under the pressure or blast created by the fan, since during the opening movement of the vanes the dash-pot plunger moves downwardly, and air flows freely past the plunger through the duct 28, raising the valve disc 29 by reason of the partial vacuum formed in the cylinder above the plunger as the latter' descends.

In Figs. 4 and 5, Iv have illustrated a slightly modified form of dash-pot, wherein, instead of providing for a restricted flow of air between the wall of the plunger 25 and the internal wall of the cylinder, I give the plunger a sliding fit in thev cylinder, and provide for a restricted flow of air during the rising movement of the plunger through a line transverse groove 3() in the top face of the plunger communicating with the upper end of the duct 28, preferably through a shallow countersink 31 in the top face of the plunger; the plunger 25 being provided with the same valve disc 29 asin the structure illustrated in Figs. 1 and 2. In ,this construction, when the plunger 25 rises under the gravity-closing movements `of the shutter vanes, the air trapped above the plunger will slowly work down through the fine groove 30, counter sink 31 and duct 28, thus retarding the gravityclosing movements of the shutter vanes; but when the fan starts up, the vanes will open freely under the air blast created by the fan, and air, due to the pressure differential between the inside portion of the cylinder above the piston and the outside atmosphere, will flow freely upward through duct 28 and counter sink 31, lifting the Valve disc 29 and equalizing the air pressures above and below the piston.

By the use of the present improvement, the rattling and slamming of the vanes under the action of wind is effectively prevented, since the closing movements of the blades are cushioned and consequently the blades close quietly. y

The piston of the dash-pot is preferably made of graphite, so as to reduce friction and` avoid the necessity of lubrication.

While I have herein illustrated and described one practical embodiment of the in-l vention, I do not limit the latter to the specific details shown, except to the extent clearly indicated in specific claims.k

I claim:

1. The combination with a fan, and a movable shutter adapted to be opened by the fan blast and to automatically close when the fan stops, of pneumatic means for damping the closing movement of the shutter.

2. The combination with a fan, and a pivoted gravity-closing shutter vane adapted to be opened by the fan blast and to automatcally close when the fan stops, of pneumatic means for damping the closing movement of the shutter vane.

ARTHUR G. SUTCLIFFE. 

